What is a luxating patella?
A luxating patella, also known as a floating kneecap, is a condition in which the kneecap (patella) dislocates, or moves out of its normal groove. The result of a dislocated kneecap is an inability to extend the leg properly at the knee joint.
Dogs who suffer from this problem often appear fine and remain very active; they will continue to run and play as normal. Owners may suddenly notice their dog go lame, picking up a hind leg. This experience can be painful, so you may hear your pet cry out while holding the back leg off the ground.
After a moment, the rear leg will lower back down to the ground, and your dog will carry on as usual. As the patella can only return to its normal position once the quadriceps muscles in your pet’s affected leg has relaxed and lengthened, it may take a few minutes before your dog lowers the leg again.
Which dogs are at risk of patella luxation?
A patella luxation is more likely to occur in a small or toy breed, such as a Poodle, Pekingese, Chihuahua, Lhasa Apso, Boston Bull, or Pomeranian. However, dogs of all sizes can be affected.
If your dog has a very flat patella ridge, the kneecap won’t sit as securely in the groove. This means the kneecap can pop out either laterally, to the outside (more common in larger breeds), or medially, to the inside (more common in smaller dogs).
Severity of the condition
There are four levels of severity for the condition, with Grade 1 being the mildest. In this case, the kneecap will pop right back in on its own. In Grade 2, it won’t always do so automatically and may require manual manipulation. With the third grade, the patella will sit outside the groove most of the time, but can temporarily be positioned back manually. In the most severe case, Grade 4, the patella will sit outside of the groove at all times. In this instance, it will not stay in place, even if you attempt to manually pop it into place.
What are the treatments?
Recommended treatment may depend on the age of the dog and the severity of the condition. Preventative treatment can help to avert joint degeneration and diminished quality of life. However, surgery will typically be recommended for a dog that suffers from a floating kneecap if they are above a Grade 1.
At the Arkansas Veterinary Surgery Center, we highly recommend you take measures to correct the issue, even if diagnosed with a mild case. If left untreated, the patellar ridge will wear over time, causing the groove to become shallower.
Your pet will become progressively lamer, and you will find that the joint will be prematurely affected by arthritis. Your veterinary surgeon will conduct a proper evaluation and recommend the right treatment option. If necessary, we can treat your pet in our orthopedic veterinary surgery.
What does the Luxating Patella Surgery involve?
The type of surgery for a patella luxation will depend on which structures in the knees are abnormal and to what degree. There are three surgical procedures for this condition:
Lateral imbrication: The aim is to keep the patella in alignment by reinforcing the weak lateral collateral ligaments. This surgery can be sufficient for mild cases.
Trochlear modification: This surgery involves deepening the trochlear groove in order to hold the kneecap in track.
Tibial crest transposition: In more severe cases, relocation of the tibial attachment may be necessary. This involves removing the point of attachment and some of the underlying bone. It will then be reattached further laterally to allow it to move as needed.
What is the prognosis following surgery?
Few complications occur post-surgery, as the surgery is relatively straightforward.
Is any post-operative care required after surgery?
Yes, your dog will likely need exercise restraint until adequately healed. Your pet will probably be prescribed antibiotics and will need limited exercise for three to four weeks in the case of a lateral imbrication, and six to eight weeks if more extensive procedures were performed. To help prevent muscle contraction, physical therapy may also be required.
The Arkansas Veterinary Surgery Center is a regional referral surgery center for orthopedic surgery on dogs, cats, and some exotic species. We are part of South County Animal Hospital in Greenwood, Arkansas. Our chief surgeon is Dr. Mark E. Sharp a graduate of the College of Veterinary Medicine at Oklahoma State University. We do both mobile surgery at your regular vet’s office and surgeries at our hospital. If you have a pet in need of a skilled surgeon for orthopedic procedures call us at 479-996-6095